1. Field of the Invention
The present invention relates to a display control system in a display device, and more particularly to a split image display control.
2. Description of the Prior Art
A split image display technique for controlling the display of split images has been known. The display control for this purpose has been implemented in two forms, i.e., a software system and a hardware system.
The software system comprises an image memory which physically corresponds to a display screen and stores information to be displayed, and a display information memory which stores coded display information. The image memory is divided into a plurality of areas by physical addresses and the display information of a selected area of the display information memory is transferred to the divisional areas.
Disadvantages of this system are that the display information must be transferred and that address translation is required therefor and hence a long processing time is required.
The hardware system is called a multi-window system. It has a memory for storing display information. The display information is read out of a plurality of areas of the memory by a hardware control and it is displayed on one display screen. A disadvantage of this system is that the control hardware is complex and of large scale as the number of areas read out (that is, the number of windows or the number of split images) increases, and hence the cost of the device increases. It also has a disadvantage of a low freedom of image splitting.